For the last few years we've been battling a major problem with honey fungus.
It has wiped out one entire side of our garden, taking with it a Norwegian spruce, hawthorn, rosemary, 3 large ceanothus bushes, 2 grapevines, a laurel and a cotoneaster tree as well as a number of smaller shrubs.
At first I couldn't understand what was killing everything on that side of the garden, but eventually I spotted the white fungal tissue below the bark near the base of a grapevine. A few weeks later (in November 2013) I saw this on one of our trees:
The RHS recommends excavating and destroying all of the infected root and stump material, but in a town garden like ours that would mean demolishing our neighbours' houses to get at all of the roots!
Instead we have had to make do with excavating the border as much as possible, and have re-planted with plants with higher resistance to honey fungus. You can find a list here: https://www.rhs.org.uk/advice/pdfs/honey-fungus-host-list.
The new plants will need time to grow so it will take a few years before we know whether we've been succesful.